package com.example.redistest.config;


import org.apache.tomcat.util.codec.binary.Base64;
import org.apache.tomcat.util.http.fileupload.IOUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

import javax.crypto.Cipher;
import java.io.ByteArrayOutputStream;
import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;

public class StringEncUtil {

    private static final Logger LOGGER = LoggerFactory.getLogger(StringEncUtil.class);

    public static final String CHARSET = "UTF-8";
    public static final String RSA_ALGORITHM = "RSA"; // ALGORITHM ['ælgərɪð(ə)m] 算法的意思


    // 公钥
    private static String publicKey = "MFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBAK000uFf6vwnWGGxRioIDOyzR6p4_L3cylmuh4mOfN-NLhBXGmOm2DLsFe_B1H0Z_O4ySkRDVAj8pEKP5pyo_rMCAwEAAQ";

    //私钥
    private static String privateKey = "MIIBVQIBADANBgkqhkiG9w0BAQEFAASCAT8wggE7AgEAAkEArTTS4V_q_CdYYbFGKggM7LNHqnj8vdzKWa6HiY58340uEFcaY6bYMuwV78HUfRn87jJKRENUCPykQo_mnKj-swIDAQABAkBw2HuUDnQAeHninCbEd55EEMHeVRkFcfX72_O-MTE2S6eWuQEDngwrnyL3qNE7QFekVYQobCWsqgEhen-43TthAiEA5VcG9rWbYrGXwYuU4c-hIuoTQZHriWqdnKTOzQy9KKsCIQDBV04yyPh6bG7ToAZhAhizbKQ6rSMNun4TgKp3G_wSGQIhAKynOczdp59DR5YjuO_O2eZpBhok-oc3RnS49h8UaguFAiEApxdL5soXLL6PnWece7QzIsXOvUMqm0_EbBhzulK-K-kCIArpxCsgtoNYianQUfztPkXVYSFO5WMoFby3A6XFmadK";


    /**
     * 得到公钥
     *
     * @param publicKey 密钥字符串（经过base64编码）
     * @throws Exception
     */
    public static RSAPublicKey getPublicKey(String publicKey) throws NoSuchAlgorithmException, InvalidKeySpecException {
        // 通过X509编码的Key指令获得公钥对象
        KeyFactory keyFactory = KeyFactory.getInstance(RSA_ALGORITHM);
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(Base64.decodeBase64(publicKey));
        RSAPublicKey key = (RSAPublicKey) keyFactory.generatePublic(x509KeySpec);
        return key;
    }

    /**
     * 得到私钥
     *
     * @param privateKey 密钥字符串（经过base64编码）
     * @throws Exception
     */
    public static RSAPrivateKey getPrivateKey(String privateKey) throws NoSuchAlgorithmException, InvalidKeySpecException {
        // 通过PKCS#8编码的Key指令获得私钥对象
        KeyFactory keyFactory = KeyFactory.getInstance(RSA_ALGORITHM);
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(Base64.decodeBase64(privateKey));
        RSAPrivateKey key = (RSAPrivateKey) keyFactory.generatePrivate(pkcs8KeySpec);
        return key;
    }

    /**
     * 公钥加密
     *
     * @param data
     * @param publicKey
     * @return
     */
    public static String publicEncrypt(String data, RSAPublicKey publicKey) {
        try {
            Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
            cipher.init(Cipher.ENCRYPT_MODE, publicKey);
            return Base64.encodeBase64URLSafeString(rsaSplitCodec(cipher, Cipher.ENCRYPT_MODE, data.getBytes(CHARSET), publicKey.getModulus().bitLength()));
        } catch (Exception e) {
            throw new RuntimeException("加密字符串[" + data + "]时遇到异常", e);
        }
    }

    /**
     * 私钥解密
     *
     * @param data
     * @param privateKey
     * @return
     */

    public static String privateDecrypt(String data, RSAPrivateKey privateKey) {
        try {
            Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
            cipher.init(Cipher.DECRYPT_MODE, privateKey);
            return new String(rsaSplitCodec(cipher, Cipher.DECRYPT_MODE, Base64.decodeBase64(data), privateKey.getModulus().bitLength()), CHARSET);
        } catch (Exception e) {
            throw new RuntimeException("解密字符串[" + data + "]时遇到异常", e);
        }
    }

    /**
     * 私钥加密
     *
     * @param data
     * @param privateKey
     * @return
     */

    public static String privateEncrypt(String data, RSAPrivateKey privateKey) {
        try {
            Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
            //每个Cipher初始化方法使用一个模式参数opmod，并用此模式初始化Cipher对象。此外还有其他参数，包括密钥key、包含密钥的证书certificate、算法参数params和随机源random。
            cipher.init(Cipher.ENCRYPT_MODE, privateKey);
            return Base64.encodeBase64URLSafeString(rsaSplitCodec(cipher, Cipher.ENCRYPT_MODE, data.getBytes(CHARSET), privateKey.getModulus().bitLength()));
        } catch (Exception e) {
            throw new RuntimeException("加密字符串[" + data + "]时遇到异常", e);
        }
    }

    /**
     * 公钥解密
     *
     * @param data
     * @param publicKey
     * @return
     */

    public static String publicDecrypt(String data, RSAPublicKey publicKey) {
        try {
            Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
            cipher.init(Cipher.DECRYPT_MODE, publicKey);
            return new String(rsaSplitCodec(cipher, Cipher.DECRYPT_MODE, Base64.decodeBase64(data), publicKey.getModulus().bitLength()), CHARSET);
        } catch (Exception e) {
            throw new RuntimeException("解密字符串[" + data + "]时遇到异常", e);
        }
    }

    //rsa切割解码  , ENCRYPT_MODE,加密数据   ,DECRYPT_MODE,解密数据
    private static byte[] rsaSplitCodec(Cipher cipher, int opmode, byte[] datas, int keySize) {
        int maxBlock = 0;  //最大块
        if (opmode == Cipher.DECRYPT_MODE) {
            maxBlock = keySize / 8;
        } else {
            maxBlock = keySize / 8 - 11;
        }
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] buff;
        int i = 0;
        try {
            while (datas.length > offSet) {
                if (datas.length - offSet > maxBlock) {
                    //可以调用以下的doFinal（）方法完成加密或解密数据：
                    buff = cipher.doFinal(datas, offSet, maxBlock);
                } else {
                    buff = cipher.doFinal(datas, offSet, datas.length - offSet);
                }
                out.write(buff, 0, buff.length);
                i++;
                offSet = i * maxBlock;
            }
        } catch (Exception e) {
            throw new RuntimeException("加解密阀值为[" + maxBlock + "]的数据时发生异常", e);
        }
        byte[] resultDatas = out.toByteArray();
        IOUtils.closeQuietly(out);
        return resultDatas;
    }

    /**
     * 解密     RAS算法
     *
     * @param strMi
     * @return
     */
    public static String getDesString(String strMi) {
        String strMing = "";
        try {
            strMing = StringEncUtil.privateDecrypt(strMi, StringEncUtil.getPrivateKey(privateKey)); //传入密文和私钥,得到明文
        } catch (Exception e) {
            strMing = "";
            LOGGER.error("getDesString error", e);
        } finally {
            return strMing;
        }
    }

    /**
     * 加密   RAS算法
     *
     * @param strMing
     * @return
     */
    public static String getEncString(String strMing) {
        String strMi = "";
        try {
            strMi = StringEncUtil.publicEncrypt(strMing, StringEncUtil.getPublicKey(publicKey));  //传入明文和公钥加密,得到密文
        } catch (Exception e) {
            strMi = "";
            LOGGER.error("getEncString error", e);
        } finally {
            return strMi;
        }

    }


    // 简单测试____________
    public static void main(String[] args) throws Exception {
//        Map<String, String> keyMap = StringEncUtil.createKeys(1024);
//        String publicKey = keyMap.get("publicKey");
//        String privateKey = keyMap.get("privateKey");
//        System.out.println("公钥: \n\r" + publicKey);
//        System.out.println("私钥： \n\r" + privateKey);
//
//        System.out.println("公钥加密——私钥解密");
//        String str = "站在大明门前守卫的禁卫军，事先没有接到\n" + "有关的命令，但看到大批盛装的官员来临，也就\n" + "以为确系举行大典，因而未加询问。进大明门即\n" + "为皇城。文武百官看到端门午门之前气氛平静，\n" + "城楼上下也无朝会的迹象，既无几案，站队点名\n" + "的御史和御前侍卫“大汉将军”也不见踪影，不免\n"
//                + "心中揣测，互相询问：所谓午朝是否讹传？";
//        System.out.println("\r明文：\r\n" + str);
//        System.out.println("\r明文大小：\r\n" + str.getBytes().length);
//        String encodedData = StringEncUtil.publicEncrypt(str, StringEncUtil.getPublicKey(publicKey));  //传入明文和公钥加密,得到密文
//        System.out.println("密文：\r\n" + encodedData);
//        String decodedData = StringEncUtil.privateDecrypt(encodedData, StringEncUtil.getPrivateKey(privateKey)); //传入密文和私钥,得到明文
//        System.out.println("解密后文字: \r\n" + decodedData);

        String strMing = "QWQCQWQWQWQW";

        String strMi = StringEncUtil.getEncString(strMing);
        System.out.println(strMi);
        String desString = StringEncUtil.getDesString("VQXVffeNrT4bJ_hDxNBIrpfMp5LsJc_aKgdRnq-Jg_HYVPTKnkiTDeIuSgu20Yh6unqCGhKQlHik5ctEGPZd3AbalUNtMg9nMzB5svg3Ufzv07pvnzrr_U4t9fZ8pfg7cZDccPbX0iEaAaEhXKFnDnYVwnSiF4bz_E6GWT4b7BE4qnMMmHhQn-DpTq-5wd44cgABW8o37NCQz_l4xm1COTL-YJncmnGpLKnRuIdFd-vymR324m6vY8DBnfaD_JdigWSdC1zpdb68ar8l9s_eHjV-2V6e4AxhpHDW7aV5UJjxvtOV488OGNT79xqqZxm3BJ3V24HIU7_wC-k53UB56DQRAVM3kGArns7EF6FLRKyRm88XFHGso6KNYcDuq7QWcrPIB0JVQ7j9n--eSa0cHrTpwtTVkYz6ysIJxm9Z9JFHALFMNCGWTfIC83M01kbTElXPuQyCZ2TfbWbtfe-5vDTD2ON0t0BnPLNj9zbLEeHqR4ZNSRiSAfnteuvlOji6");
        System.out.println(desString);
    }
}
